1. Field of the Invention
The present invention relates to a control system of a printer device, more particularly to a color printer system which issues a printing instruction from its host to perform printing by its printer.
2. Description of the Related Art
Explanations for such kind of conventional color printer system will be made with reference to FIG. 9. FIG. 9 shows an example of a construction of a conventional color printer system. Referring to FIG. 9, a host 51 comprises transmission means 52 for transmitting image data to a printer 61. The printer 61 consists of receiving means 62, analysis means 63, image transform means 64, picturing means 65 and a printer engine 66.
In this conventional color printer system, an application on the host issues a printing instruction, and transfers printing data to a printer. The printer performs printing. Moreover, the host 51 does not perform an image transform processing, but the printer 61 exclusively performs the image transform processing.
In other words, image data prepared by the application which is executed in the host 51 is directly sent to the printer 61, and the printer 61 performs a color transform, a resolution change and a gradient processing in accordance with the printer.
As an example of the conventional color printer system, there has also been known a system in which a printer does not comprise image transform means and a host exclusively performs an image transform processing. In this example, for image data prepared by an application, the host performs a color transform, a resolution change and a gradient processing in accordance with a printer, and transfers the image data to the printer. The printer performs only a printing processing.
Furthermore, there has also been known a system in which both a host and a printer comprise image transform means, and a user decides, by using a user interface, which image conversion means to use.
In the color printer system disclosed in Japanese Patent Laid-open No. 9-258940, based on data such as cyan, magenta, yellow and black for each pixel, the host decides whether or not the pixel is white, and if the pixel is white, the host transmits binary data to the printer. If the pixel is not white, the host transmits data of cyan, magenta, yellow and black. The printer develops an image based on the received data. Thus, a quantity of communication data is lessened.
However, the above described conventional system has the following problems.
The first problem is that the quantity of data transferred from the host to the printer cannot be lessened.
This is because an image transform processing is exclusively performed either by the host or by the printer.
In other words, the conventional system comprises no decision means for deciding which case of the two following cases the quantity of data to be transferred is more reduced; one being that the host performs the image transform processing and the other being that the printer performs the image transform processing. Recently, the network of the system has developed, and load on the network has increased. Under such circumstances, a decrease in the quantity of data on the network has been demanded in network printers and the like.
The second problem is that it is impossible to shorten an overall processing time taken for printing. This is because the host or the printer exclusively performs the image transform processing in the same way as the first problem.
The present invention was invented in view of the foregoing problems, and the object of the present invention is to provide a color printer system which is capable of reducing the quantity of data transferred from a host to a printer, thus shortening an overall time taken for a printing processing.
In a color printer system of the present invention which comprises a host and a printer, each of the host and the printer comprise image transform means; the host comprises image transform decision means for deciding which should be used, the image transform means of the host or the image transform means of the printer; and the image transform means decided by the image transform decision means performs a specified image transform processing.
Moreover, the host may comprise image transform decision means for deciding which case of the two following cases can more reduce the quantity of data to be transferred; one being that the host performs the image transform processing and the other being that the printer performs the image transform processing, and deciding which should be used, image transform means of the host or image transform means of the printer.
According to the present invention, in the color printer system, image transform decision means decides which case of the two following cases can more reduce the quantity of data to be transferred; one being that the host performs the image transform processing and the other being that the printer performs the image transfer processing, and based on the decision result the image transform processing is performed either by the host or the printer, so that the quantity of the data transferred from the host to the printer is decreased, and hence a time taken for the printing processing can be shortened. Furthermore, when the color printer system of the present invention is applied to a network printer, an increase in a network load owing to a printing data transfer can be suppressed.
Furthermore, since the host automatically performs the image transform decision, the quantity of data transferred from the host to the printer is decreased without being known by the user, so that a time required for the printing processing can be shortened.